Abstract

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the
Lunar Reconnaissance Orbiter (LRO) characterizes the radiation
environment to be experienced by humans during future lunar missions.
CRaTER measures the effects of ionizing energy loss in matter due to
penetrating solar energetic protons (SEP) and galactic cosmic rays
(GCR), specifically in silicon solid-state detectors and after
interactions with tissue-equivalent plastic (TEP), a synthetic analog of
human tissue. The CRaTER investigation quantifies the linear energy
transfer (LET) spectrum in these materials through direct measurements
with the lunar space radiation environment, particularly the
interactions of ions with energies above 10 MeV, which penetrate and are
detected by CRaTER. Combined with models of radiation transport through
materials, CRaTER LET measurements constrain models of the biological
effects of ionizing radiation in the lunar environment as well as
provide valuable information on radiation effects on electronic systems
in deep space. In addition to these human exploration goals, CRaTER
measurements also provide new insights on the spatial and temporal
variability of the SEP and GCR populations and their interactions with
the lunar surface. We present here an overview of the CRaTER science
goals and investigation, including: an instrument description;
observation strategies; instrument testing, characterization, and
calibration; and data analysis, interpretation, and modeling plans.